（一）从底层透析文件上传的实现，此时并没有介入struts2
1、upload.jsp，在form中属性method默认为get，涉及文件上传时必须改为post，默认
enctype="application/x-www-form-urlencoded" ，我们暂且不修改，看会有什么结果
1
<%
@ page language="java" contentType="text/html; charset=GBK"
2
pageEncoding="GBK"%>
3
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4<html>
5 <head>
6 <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
7 <title>Insert title here</title>
8 </head>
9 <body>
10 <form action="result.jsp" method="post"
11 enctype="application/x-www-form-urlencoded">
12 Information:
13 <input type="text" name="info">
14 <br>
15 File:
16 <input type="file" name="file">
17 <br>
18 <input type="submit" name="submit" value=" submit ">
19 </form>
20 </body>
21</html>
result.jsp
1<%@ page language="java" contentType="text/html; charset=GBK"
2 pageEncoding="GBK"%>
3<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4<html>
5 <head>
6 <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
7 <title>Insert title here</title>
8 </head>
9 <body>
10 Information:<%=request.getParameter("info")%><br>
11 File:<%=request.getParameter("file")%><br>
12 </body>
13</html>
结果：
2、修改result.jsp页面代码，输出读入的流
<%@ page import="java.io.*"%>
<body>
<%
InputStream is = request.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String buffer = null;
while ((buffer = br.readLine()) != null) {
out.print(buffer + "<br>");
}
%>
</body>
结果：
这个结果可以断定，文件的上传并没有成功，而仅仅是上传了文件的路径信息而已
3、把upload.jsp中form的enctype属性改为
enctype="multipart/form-data"
<form action="result.jsp" method="post" enctype="multipart/form-data">
Information:
<input type="text" name="info">
<br>
File:
<input type="file" name="file">
<br>
<input type="submit" name="submit" value=" submit ">
</form>
结果：
说明文件上传是成功的。
（二）手动采用fileupload组建进行文件上传
upload2.jsp
1<%@ page language="java" contentType="text/html; charset=GB18030"
2 pageEncoding="GB18030"%>
3<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4<html>
5 <head>
6 <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
7 <title>Insert title here</title>
8 </head>
9 <body>
10 <form action="/MyStruts2/UploadServlet" method="post" enctype="multipart/form-data">
11 username:
12 <input type="text" name="username">
13 <br>
14 password:
15 <input type="password" name="password">
16 <br>
17 file1:
18 <input type="file" name="file1">
19 <br>
20 file2:
21 <input type="file" name="file2">
22 <br>
23 <input type="submit" value=" submit ">
24 </form>
25 </body>
26</html>
web.xml中的配置
<servlet>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>com.test.servlet.UploadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/UploadServlet</url-pattern>
</servlet-mapping>
UploadServle.java
1package com.test.servlet;
2
3import java.io.File;
4import java.io.FileOutputStream;
5import java.io.IOException;
6import java.io.InputStream;
7import java.io.OutputStream;
8import java.util.List;
9
10import javax.servlet.ServletException;
11import javax.servlet.http.HttpServlet;
12import javax.servlet.http.HttpServletRequest;
13import javax.servlet.http.HttpServletResponse;
14
15import org.apache.commons.fileupload.FileItem;
16import org.apache.commons.fileupload.FileUploadException;
17import org.apache.commons.fileupload.disk.DiskFileItemFactory;
18import org.apache.commons.fileupload.servlet.ServletFileUpload;
19
20@SuppressWarnings("serial")
21public class UploadServlet extends HttpServlet {
22
@SuppressWarnings( { "unchecked", "deprecation" })
23 public void doPost(HttpServletRequest request, HttpServletResponse response)
24 throws ServletException, IOException {
25
26 DiskFileItemFactory factory = new DiskFileItemFactory();
27
28 String path = request.getRealPath("/upload");
29
30 factory.setRepository(new File(path));
31
32 factory.setSizeThreshold(1024 * 1024);
33
34 ServletFileUpload upload = new ServletFileUpload(factory);
35
36 try {
37 List<FileItem> list = upload.parseRequest(request);
38
39 for (FileItem item : list) {
40 if (item.isFormField()) {
41 String name = item.getFieldName();
42
43 String value = item.getString("gbk");
44
45 System.out.println(name);
46
47 request.setAttribute(name, value);
48 } else {
49 String name = item.getFieldName();
50
51 String value = item.getName();
52
53 int start = value.lastIndexOf("\\");
54
55 String fileName = value.substring(start + 1);
56
57 request.setAttribute(name, fileName);
58
59 item.write(new File(path, fileName));
60
61 OutputStream os = new FileOutputStream(new File(path,
62 fileName));
63
64 InputStream is = item.getInputStream();
65
66 byte[] buffer = new byte[400];
67
68 int length = 0;
69
70 while ((length = is.read(buffer)) > 0) {
71 os.write(buffer, 0, length);
72
}
73
74 os.close();
75
76 is.close();
77
78 }
79 }
80 }
81
82 catch (Exception ex) {
83 ex.printStackTrace();
84 }
85 request.getRequestDispatcher("upload/result2.jsp").forward(request,
86 response);
87 }
88
89}
结果：
（三）使用struts2进行文件上传、下载
需引入两个jar包
commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
这两个jar包在struts2.1.6版本中已经自带，较低版本需到apache网站下载，网址：
http://commons.apache.org/1、单文件上传
upload3.jsp
1<%@ page language="java" contentType="text/html; charset=GB18030"
2 pageEncoding="GB18030"%>
3<%@ taglib prefix="s" uri="/struts-tags"%>
4<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5<html>
6 <head>
7 <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
8 <title>Insert title here</title>
9 </head>
10 <body>
11 <s:form action="upload" method="post" theme="simple"
12 enctype="multipart/form-data">
13 <table align="center" width="50%" border="1">
14 <tr>
15 <td>
16 username
17 </td>
18 <td>
19 <s:textfield name="username"></s:textfield>
20 </td>
21 </tr>
22 <tr>
23 <td>
24 password
25 </td>
26 <td>
27 <s:password name="password"></s:password>
28 </td>
29 </tr>
30 <tr>
31 <td>
32 file
33 </td>
34
35 <td>
36 <s:file name="file"></s:file>
37
38 </td>
39 </tr>
40 <tr>
41 <td>
42 <s:submit value=" submit "></s:submit>
43 </td>
44 <td>
45 <s:reset value=" reset "></s:reset>
46 </td>
47 </tr>
48 </table>
49 </s:form>
50 </body>
51</html>
web.xml中的配置
<filter>
<filter-name>struts2</filter-name>
<filter-class>
org.apache.struts2.dispatcher.FilterDispatcher
</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
struts.xml中的配置
1<?xml version="1.0" encoding="GBK" ?>
2<!DOCTYPE struts PUBLIC
3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
4 "http://struts.apache.org/dtds/struts-2.0.dtd">
5
6<struts>
7 <constant name="struts.i18n.encoding" value="gbk"></constant>
8 <constant name="struts.multipart.saveDir" value="c:\"></constant>
9 <package name="struts2" extends="struts-default">
10 <action name="upload" class="com.test.action.UploadAction">
11 <result name="success">/upload/result3.jsp</result>
12 </action>
13 </package>
14</struts>
UploadAction.java
1package com.test.action;
2
3import java.io.File;
4import java.io.FileInputStream;
5import java.io.FileOutputStream;
6import java.io.InputStream;
7import java.io.OutputStream;
8
9import org.apache.struts2.ServletActionContext;
10
11import com.opensymphony.xwork2.ActionSupport;
12
13@SuppressWarnings("serial")
14public class UploadAction extends ActionSupport {
15 private String username;
16 private String password;
17 private File file;
18 private String fileFileName;
19 private String fileContentType;
20
21 public String getUsername() {
22 return username;
23 }
24
25 public void setUsername(String username) {
26 this.username = username;
27 }
28
29 public String getPassword() {
30 return password;
31 }
32
33 public void setPassword(String password) {
34 this.password = password;
35 }
36
37 public File getFile() {
38 return file;
39 }
40
41 public void setFile(File file) {
42 this.file = file;
43 }
44
45 public String getFileFileName() {
46 return fileFileName;
47 }
48
49 public void setFileFileName(String fileFileName) {
50 this.fileFileName = fileFileName;
51 }
52
53 public String getFileContentType() {
54 return fileContentType;
55 }
56
57 public void setFileContentType(String fileContentType) {
58 this.fileContentType = fileContentType;
59 }
60
61 @SuppressWarnings("deprecation")
62 @Override
63 public String execute() throws Exception {
64 InputStream is = new FileInputStream(file);
65 String root = ServletActionContext.getRequest().getRealPath("/upload");
66 File destFile = new File(root, this.getFileFileName());
67 OutputStream os = new FileOutputStream(destFile);
68 byte[] buffer = new byte[400];
69
70 int length = 0;
71
72 while ((length = is.read(buffer)) > 0) {
73 os.write(buffer, 0, length);
74 }
75 is.close();
76 os.close();
77 return SUCCESS;
78 }
79}
结果：
2、多文件上传
修改action
private List<File> file;
private List<String> fileFileName;
private List<String> fileContentType;
public String execute() throws Exception {
for (int i = 0; i < file.size(); ++i) {
InputStream is = new FileInputStream(file.get(i));
String root = ServletActionContext.getRequest().getRealPath(
"/upload");
File destFile = new File(root, this.getFileFileName().get(i));
OutputStream os = new FileOutputStream(destFile);
byte[] buffer = new byte[400];
int length = 0;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
is.close();
os.close();
}
return SUCCESS;
}
修改upload3.jsp
<tr>
<td>
file1
</td>
<td>
<s:file name="file"></s:file>
</td>
</tr>
<tr>
<td>
file2
</td>
<td>
<s:file name="file"></s:file>
</td>
</tr>
<tr>
<td>
file3
</td>
<td>
<s:file name="file"></s:file>
</td>
</tr>
结果：
3、任意数量文件上传
在多文件上传的基础上修改upload3.jsp
<script type="text/javascript">
function addMore()
{
var td = document.getElementById("more");
var br = document.createElement("br");
var input = document.createElement("input");
var button = document.createElement("input");
input.type = "file";
input.name = "file";
button.type = "button";
button.value = "Remove";
button.onclick = function()
{
td.removeChild(br);
td.removeChild(input);
td.removeChild(button);
}
td.appendChild(br);
td.appendChild(input);
td.appendChild(button);
}
</script>
<tr>
<td>
file1
</td>
<td id="more">
<s:file name="file"></s:file>
<input type="button" value="Add More.." onclick="addMore()">
</td>
</tr>
结果：
（四）文件上传类型、大小的限制
使用struts的拦截器，struts2-core-2.1.6.jar/org.apache.struts2.interceptor.FileUploadInterceptor.class的源码中我们可以看到：
public class FileUploadInterceptor extends AbstractInterceptor {
private static final long serialVersionUID = -4764627478894962478L;
protected static final Logger LOG = LoggerFactory.getLogger(FileUploadInterceptor.class);
private static final String DEFAULT_MESSAGE = "no.message.found";
protected boolean useActionMessageBundle;
protected Long maximumSize;
protected Set<String> allowedTypesSet = Collections.emptySet();
protected Set<String> allowedExtensionsSet = Collections.emptySet();
所以我们只需的struts.xml中配置它的属性allowedTypesSet即可。在action节点中修改拦截器（默认的拦截器中已经有fileUpload拦截器，我们必须提取出来进行参数设置，然后在加上默认的拦截器）。
<action name="upload" class="com.test.action.UploadAction">
<result name="success">/upload/result3.jsp</result>
<result name="input">/upload/upload3.jsp</result>
<interceptor-ref name="fileUpload">
<param name="maximumSize">409600</param>
<param name="allowedTypes">
application/vnd.ms-powerpoint
</param>
</interceptor-ref>
<interceptor-ref name="defaultStack"></interceptor-ref>
</action>
其中
<param name="allowedTypes">application/vnd.ms-powerpoint</param>的allowedTypes的值可在C:\Tomcat 6.0\conf的web.xml文件中查找。
报错信息：
严重: Content-Type not allowed: file "intrl.txt" "upload__138d8aca_120b73e9cf4__8000_00000002.tmp" text/plain
（五）文件的下载
download.jsp
<s:a href="/MyStruts2/download.action">download</s:a>
DownloadAction.java
1package com.test.action;
2
3import java.io.InputStream;
4
5import org.apache.struts2.ServletActionContext;
6
7import com.opensymphony.xwork2.ActionSupport;
8
9public class DownloadAction extends ActionSupport {
10 public InputStream getDownloadFile() {
11 return ServletActionContext.getServletContext().getResourceAsStream(
12 "/upload/intrl.ppt");
13 }
14
15 @Override
16 public String execute() throws Exception {
17 return SUCCESS;
18 }
19}
20
web.xml中action配置
<action name="download"
class="com.test.action.DownloadAction">
<result name="success" type="stream">
<param name="contentType">
application/vnd.ms-powerpoint
</param>
<param name="contentDisposition">
filename="intrl.ppt"
</param>
<param name="inputName">downloadFile</param>
</result>
</action>
结果：
